Okay so Ive explained most of the stuff in the notes of each section. This wont be a SUPER detailed guide BUT it will give you all the tools you need to play a mean Gnar :P

For items the core dmg and only dmg item will be BOTRK. It suits his play style so well and I NEVER plat Gnar without it. Being that youre mostly going to be tank, the % dmg is perfect for the lack of many dmg items. It gives sustain, AS, and it synergizes very well with his % dmg W passive. Along with the items active you be sticking on your enemies with ease, and dont forget to laugh as they desperately try to claw away before being taken down by the cute widdle monster. Now I like to run AS boots to help proc more W passive, but its completely up to the situation. You know the drill. :P The rest of your kit will be BEEF, cause its whats for dinner. Well theyre for dinner.. Basically as Gnar youre going to want to initiate so you need that tank, but make no mistake.. Especially with BOTRK youll be pumping out some SERIOUS dmg. Deleting the squishies, and Gnar also shreds tanks very well too. Hes a very versatile champion
which is one of the reasons I love him so much. Also Gnars W passive % dmg and his Ulti are both magic dmg, so if youre in a match that you feel you can hold back on the tank, a Void Staff can really make those abilities hurt. This is great because if they are building armor your AP dmg is still going to cut through.

For the abilities, youre almost always going to want to max Q 1st. In some cases I like to put 3 into W if Im fighting a really tank opponent. But you want that Q CD low so you can spam it at your foe and annoy the **** out of them. Also the slow is very important to stick on them and get the W passive procd per 3 hits. Always save you E for escapes unless youre going all in for instance in Mega form to jump and R them into walls for you team to come and clean up the mess you certainly made of them :P During lane phase W passive is very important to you harass, but very obvious.. What I suggest is to AA > Q > AA fast to get those quick procs off. His ult can be very useful defensively and offensively. Like I said earlier, you want to slam them against the wall to get that extra dmg but more importantly the stun. The combo I use Is R into the wall, and right when the ulti stun is up, W them for another stun, and then Q them after that one runs. Its a VERY effective lockdown leaving as many as all 5 of them useless! And for defensively, the enemy team could be about to kill your team mates and you can R them in the other direction to effectively save your pretties :) Managing your rage, for some, seems inconvenient or hard to manage. But I promise over time with practice on Gnar, you will get the feel of it and will basically subconsciously manage it, really all up to practice. But in some cases you may feel an engage coming soon and hit some minions or jun monsters to gain some rage so that you may jump in in your mega form.

I mainly run tank masteries for the obvious. I also grab Oppressor because Gnars kit is LOADED with stuns and slows.

For runes its really up to you.. But heres what I run. Like I said, it really doesnt matter much, anything works.